BULETINUL INSTITUTULUI POLITEHNIC DIN IAŞI
buletinul institutului politehnic din iaşi - Universitatea Tehnică ...
buletinul institutului politehnic din iaşi - Universitatea Tehnică ...
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108 Vlad Marţian et al<br />
that all the components are constant, whereas in reality all these characteristics<br />
are dependent of the SOC, and the dicharge current. The circuit diagram can be<br />
seen in the Fig. 2.<br />
Fig. 2 – Thervein model.<br />
2.3. Non linear Dynamic Model<br />
A more realistic model has been created by extending the Thervein<br />
model. This new model takes into account the nonlinearities in the components<br />
of the Thervein model. As we said earlier the internal resistance of the battery<br />
R+R 0 and the open circuit voltage E 0 are dependent on the SOC of the battery,<br />
and also on the temperature T of the battery.<br />
Since we are interested in how the temperature of the battery changes in<br />
time we will use a modification of this later model, which can be seen in a<br />
simplified version in Fig. 3.<br />
In this model different form Thervein model we have included the<br />
internal resistance in the overvoltage resistance, for simplification purpose, and<br />
the internal resistance R and the open circuit voltage E 0 are dependent on some<br />
function of SOC.<br />
Fig. 3 – Non linear dynamic model.<br />
3. Modeling Implementation<br />
If we want to know how the current and the voltage in the battery are<br />
modified in time we have to solve a system of equations that include first order<br />
differential equations and also algebraic equations. Doing it by hand it takes a<br />
long time, and if one of the parameter is changed we will have to do it again.